Evaluation of the number and distribution of synaptic vesicles at cholinergic nerve-endings after sustained stimulation

Perri, V.; Sacchi, Oscar; Raviola, Elio; Raviola, Giuseppina

doi:10.1016/0006-8993(72)90458-1

Cited by 42 publications

(24 citation statements)

References 15 publications

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“…Since C fibre conduction is not affected by antithiamine treatment, at least in the conditions adopted for these experiments [Sacchi and Perri, 1969], a reduced number of active ganglion neurons and increased delays in their activation processes are the only possible explanations of the changes noted in the post-ganglionic potential. A decrease in the number of active units is very likely to be the result of oxythiamine action owing to the dramatic reduction it produces in the amplitude of the post-ganglionic potential.…”

Section: Discussionmentioning

confidence: 95%

Action of Oxythiamine and Pyrithiamine on the Isolated Rat Superior Cervical Ganglion

1970

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Incubation of isolated preparations of the superior cervical ganglion of the rat in the presence of low concentrations of oxythiamine and pyrithiamine results in an early and pronounced decrease of the post-ganglionic potential. This effect is particularly evident with regard to oxythiamine.The depressant action of both antithiamines on ganglion transmission appears to be specifically due to their metabolic competition because it can be completely prevented by the presence of equimolecular amounts of thiamine in the incubating medium.As reported in the preceding paper, thiamine deficiency induced in rats by dietary avitaminosis, produces an early impairment of the superior cervical ganglion's ability to transmit nerve impulses at high frequency [Perri, Sacchi and Casella, 1970].In order to obtain further information on the role of thiamine in the function of sympathetic ganglia we have investigated whether in vitro treatment of isolated rat cervical ganglia with thiamine antagonists can produce alterations similar to those observed in dietary B1 avitaminosis.We tested two different thiamine antagonists, pyrithiamine and oxythiamine, which are believed to act through different mechanisms and whose effects, particularly on nervous function, differ considerably. It is well known that treatment with pyrithiamine consistently leads to the appearance of nervous symptoms typical of B1 avitaminosis, whereas oxythiamine does not appear to have any appreciable effects on the nervous system either in vivo or in vitro [Koedam, Steyn-Parve and van Rheenen, 1956;De Caro, Rindi, Perri and Ferrari, 1956;Kunz, 1956;Gurtner, 1961;Armett and Cooper, 1965].The post-ganglionic potential was recorded from isolated superior cervical ganglia of the rat, incubated in the presence of small amounts of oxythiamine and pyrithiamine. The influence of these substances on ganglion transmission was tested at different stimulation frequencies; experiments were also performed to ascertain whether the presence of adequate amounts of thiamine in the incubation medium can prevent or possibly reverse the alterations in ganglion function induced by the antithiamines. METHODSEighty male Wistar rats of 90-100 g body weight were used. The superior cervical ganglion was isolated together with the cervical sympathetic cord and the internal carotid nerve, according to the procedure described in the preceding paper [Perri, Sacchi and Casella, 1970]; the preparations were placed in a perspex cell filled with a 36

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Section: Discussionmentioning

confidence: 95%

Action of Oxythiamine and Pyrithiamine on the Isolated Rat Superior Cervical Ganglion

1970

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“…Perri et al (1972) showed that although prolonged stimulation (3.5 h at 0*5 Hz followed by 30 min at 20Hz) reduced the over-all vesicle population, vesicle numbers within 0-14 um of the presynaptic membrane were unaffected. This supports the view that the present observations of increases in the local vesicle population do not necessarily reflect an over-all increase in vesicle numbers and could even have been associated with reductions in vesicle densities remote from the marginal band.…”

Section: Discussionmentioning

confidence: 98%

“…Comparison with the observations of other workers is complicated by the variety of preparations and of fixation techniques employed which do not yield comparable control vesicle populations, and because most authors have used more severe stimulation than ourselves, usually with the stated or implied aim of producing a reduction in vesicle population, an aim in which they have been successful (Friessen & Khatter, 1971;Pysh & Wiley, 1972;Perri et al 1972;Korneliussen, 1972).…”

Section: Discussionmentioning

confidence: 99%

“…Different fixation techniques may yield different control vesicle populations, possibly due to differences in shrinkage or swelling of the tissue, possibly to differential retention of vesicles during fixation. For example, Perri et al (1972) obtained higher populations in aldehyde fixed rat superior cervical ganglia than in osmium fixed ganglia, but there is no means of assessing what technique preserves the 'living' ultrastructure most faithfully. Nevertheless, with a consistent technique of fixation and subsequent preparation, modifications to the living ultrastructure should be consistent so that control and experimental material can be compared safely.…”

Section: Electron Microscopymentioning

confidence: 99%

“…Patrducz, Feher & Joo (1971), Friessen & Khatter (1971) and Pysh & Wiley (1972) have reported findings on synaptic vesicle populations in the superior cervical ganglion of the cat while Perri, Sacchi, Raviola & Raviola (1972) studied rat superior cervical ganglia. Comparison of the results of these various workers with one another or with ours is not easy since no two groups appeared to employ similar experimental conditions nor to count vesicle populations in the same part of the presynaptic profile.…”

Section: Introductionmentioning

confidence: 99%

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Some effects of preganglionic nerve stimulation on synaptic vesicle populations in the rat superior cervical ganglion

Quilliam¹,

Tamarind²

1973

The Journal of Physiology

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SUMMARY1. The 'local vesicle population', namely the population of synaptic vesicles lying within a zone 0-25 Am wide adjacent to the presynaptic membrane and expressed as 'vesicles ,um-2' has been estimated in rat superior cervical ganglia maintained in vitro for 1 h. Ganglia were either unstimulated or stimulated tetanically during the last few minutes of the in vitro period.2. Individual local vesicle populations at synapses in groups of ganglia which had received the same treatment showed an approximately normal frequency distribution.3. The technique of stimulation did not permit fixation during tetanus, but the mean local vesicle population in ganglia fixed a few seconds after 10 Hz tetani of up to 10 min duration were significantly (P < 0.001) higher than the unstimulated control value of 124*0 + s.E. 3-2. Ganglia fixed a few seconds after 3 min tetani at 10 Hz had a mean local vesicle population of 155*7 + s.E. 5*7, rising slightly but not significantly to 165-0 + s.x. 4*3 at 1 min and 163-1 + s.E. 5-2 at 2 min after tetanus. Thereafter the mean local vesicle population fell slowly, reaching control level between 10 and 20 min after tetanus.4. In terms of the vesicle hypothesis, the observations suggest that post-tetanic potentiation might arise from a closer clustering of vesicles about release areas resulting in an increase in fractional release. It is suggested that stimulation increased the local vesicle population by promoting vesicle mobilization rather than by altering the size or shape of the presynaptic terminals. The 'mobilizing agent' might be intracellular Ca2 .5. The results appear to be consistent with those of other workers where experimental conditions and the region in which vesicles were counted were comparable.

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Structure of the Synapse

Heuser

Reese

1977

Comprehensive Physiology

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Evaluation of the number and distribution of synaptic vesicles at cholinergic nerve-endings after sustained stimulation

Cited by 42 publications

References 15 publications

Action of Oxythiamine and Pyrithiamine on the Isolated Rat Superior Cervical Ganglion

Action of Oxythiamine and Pyrithiamine on the Isolated Rat Superior Cervical Ganglion

Some effects of preganglionic nerve stimulation on synaptic vesicle populations in the rat superior cervical ganglion

Structure of the Synapse

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